The present disclosure is generally directed to semiconductors of the formulas as illustrated herein and processes of preparation and uses thereof. More specifically, the present disclosure in embodiments is directed to novel polymers of the formulas as illustrated herein, and more specifically, to poly(dithienylbenzo[1,2-b:4,5-b′]dithiophene)s selected as semiconductors for polymer thin-film transistors and also which can be selected as solution processable and substantially stable channel semiconductors in organic electronic devices, such as thin film transistors and which transistors are stable in air, that is do not substantially degrade over a period of time when exposed to oxygen. Although not desiring to be limited by theory, it is believed that the presence of two thienylene functions in the semiconductor polymer assists in enhancing transistor performance, such as field effect mobility, for example there can be achieved TFT field effect mobility of 10−2 cm−2/v.s.
There are desired electronic devices and polymers thereof, such as thin film transistors, TFTs, fabricated with a semiconductor of the formulas as illustrated herein, and which semiconductors possess excellent solvent solubility, and which can be solution processable; and which devices possess mechanical durability and structural flexibility, characteristics which are desirable for fabricating flexible TFTs on a number of substrates, such as plastic substrates. Flexible TFTs enable the design of electronic devices with structural flexibility and mechanical durability characteristics. The use of plastic substrates together with the semiconductor of the formulas as illustrated herein can transform the traditionally rigid silicon TFT into a mechanically more durable and structurally flexible TFT design. This can be of particular value to large area devices such as large-area image sensors, electronic paper and other display media. Also, the selection of p-type semiconductors of the formulas as illustrated herein possess in embodiments extended conjugation for integrated circuit logic elements for low end microelectronics, such as smart cards, radio frequency identification (RFID) tags, and memory/storage devices, and enhance their mechanical durability, and thus their useful life span.
A number of semiconductor polymers are not, it is believed, stable when exposed to air as they become oxidatively doped by ambient oxygen resulting in increased conductivity. The result is large off-current and thus low current on/off ratio for the devices fabricated from these materials. Accordingly, with many of these polymers, rigorous precautions are usually undertaken during processing and device fabrication to exclude environmental oxygen to avoid or minimize oxidative doping. These precautionary measures increase the cost of manufacturing therefore offsetting the appeal of certain semiconductor TFTs as an economical alternative to amorphous silicon technology, particularly for large area devices. These and other disadvantages are avoided or minimized in embodiments of the present disclosure.